Overview
ISO/TR 8941:2024 is a Technical Report from ISO that explains the types and modes of operation of rail mounted construction, maintenance and inspection machines used on railway infrastructure. Published in 2024 by ISO/TC 269 (Railway applications), the report clarifies the complex variety of machines fitted with rail wheels - including on-track machines (OTMs), infrastructure inspection vehicles, environment vehicles, emergency vehicles, road-rail machines, trolleys and portable machines - and provides a common vocabulary and classification approach for the sector.
Key Topics and Requirements
The report focuses on classification, operational definitions and acceptance-related considerations rather than prescriptive technical specifications. Key topics include:
- Definitions and terminology for rail mounted machines, including railbound machines (with and without running mode), road-rail machines, trailers, demountable machines, trolleys and portable machines.
- Operational modes:
- Running mode - machine interacts with signalling and control systems; moveable parts stowed within gauge.
- Travelling mode - movement along working track without interacting with signalling systems; moveable parts stowed but not secured.
- Working mode - machine performs its designed tasks under operational controls.
- Generic machine types and classification: methods to classify machines by capability (running mode, road mode), ways of moving on track, demountable modules and attachments.
- Acceptance and compliance considerations: interface with machinery standards, railway standards and the processes for acceptance to work on the railway.
- Informative Annex A with examples of machine types to aid interpretation.
Note: ISO/TR 8941:2024 contains no normative references; it is intended as explanatory guidance and introduction to machine types.
Applications - Who Uses This Standard
ISO/TR 8941:2024 is useful to professionals involved in railway infrastructure lifecycle and safety, including:
- Infrastructure managers who set operational rules and acceptance criteria.
- Manufacturers and designers of OTMs, road-rail machines and portable/portable track equipment.
- Procurement and asset managers defining functional requirements and machine classification.
- Safety and signalling engineers assessing interaction between machines and control systems.
- Regulators and standards bodies harmonizing terminology and classification across networks.
Practical uses include standardizing machine descriptions in specifications, clarifying operational modes for planning track possessions, and aligning acceptance testing with railway and machinery standards.
Related Standards (if applicable)
- ISO/TC 269 Railway applications (committee responsible for this report).
- Machinery standards and national/regional railway technical rules referenced in acceptance processes (consult infrastructure manager and national standards bodies for specific normative requirements).
Keywords: ISO/TR 8941, rail mounted machines, on-track machines, OTMs, infrastructure inspection vehicles, road-rail machines, running mode, travelling mode, working mode, railway infrastructure.